linux-kernel - [PATCH 5/5] m68k,mm: Fully initialize the page-table allocator

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Message-Id: <20200129104345.548344561@infradead.org>
Date:   Wed, 29 Jan 2020 11:39:46 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     linux-m68k@...ts.linux-m68k.org, linux-kernel@...r.kernel.org,
        Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 5/5] m68k,mm: Fully initialize the page-table allocator

Also iterate the PMD tables to populate the PTE table allocator. This
also fully replaces the previous zero_pgtable hack.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/m68k/mm/init.c |   23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

--- a/arch/m68k/mm/init.c
+++ b/arch/m68k/mm/init.c
@@ -124,15 +124,30 @@ void free_initmem(void)
 static inline void init_pointer_tables(void)
 {
 #if defined(CONFIG_MMU) && !defined(CONFIG_SUN3) && !defined(CONFIG_COLDFIRE)
-	int i;
+	int i, j;
 
 	/* insert pointer tables allocated so far into the tablelist */
 	init_pointer_table((unsigned long)kernel_pg_dir, 0);
 	for (i = 0; i < PTRS_PER_PGD; i++) {
-		pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
+		pud_t *pud = (pud_t *)&kernel_pg_dir[i];
+		pmd_t *pmd_dir;
 
-		if (pud_present(*pud))
-			init_pointer_table(pgd_page_vaddr(kernel_pg_dir[i]), 0);
+		if (!pud_present(*pud))
+			continue;
+
+		pmd_dir = (pmd_t *)pgd_page_vaddr(kernel_pg_dir[i]);
+		init_pointer_table((unsigned long)pmd_dir, 0);
+
+		for (j = 0; j < PTRS_PER_PMD; j++) {
+			pmd_t *pmd = &pmd_dir[j];
+			pte_t *pte_dir;
+
+			if (!pmd_present(*pmd))
+				continue;
+
+			pte_dir = (pte_t *)__pmd_page(*pmd);
+			init_pointer_table((unsigned long)pte_dir, 1);
+		}
 	}
 #endif
 }